Fluid compressor



Sept. 26, 1933. C -c FARMER FLUID COMPRESSOR 2 Sheets-Sheet 1 Filed July 2, 1951 INVENTOR.

LYDE 2. FARMER' ATTORNEY.

Sept. 26, 1933.

c. c. FARMER FIJUID COMPRESSOR Filed July 2, 1931 2 Sheets-Sheet 2 INVENTOR.

cums c. FARMER BY ATTORNEY.

Patented Sept. 26, 1933 UNITED STATES FLUID COMPRESSOR" l Clyde 0. Farmer, Pittsburgh, Pa., assignor to The Westinghouse Air Brake Cmpany,-Wilmerding, Pa., a corporation of Pennsylvania Application July 2, 1931. Serial No. 548,361

14 Claims; (01. 230-211) This invention relates to air compressors and more particularly to cooling systems therefor.

One object of the present invention is the provision in a motor compressor unit of means for inducing a flow of cooling fluid over the compressor to absorb heat generated during its operation.

Another object resides in effecting increased efficiency of the compressor by the inclusion of an improved cooling system adapted to effectively reduce the temperature of compressed air passing from one cylinder to another.

A further object of the invention is to provide independent cooling chambers for the compressor and intercooling coils under the influence of a single means for inducing a flow of fluid through each of said chambers to cool the compressor and coils.

Another object of the present invention is the provision of fan means directly connected to the compressor for inducing a flow of fluid through the compressor and coil housings to subject each to an independent source of cooling fluid.

' A more specific object resides in the provision of means for maintaining substantially equal pressures upon opposite sides of the compressor end bearing adjacent the fan to insure against the withdrawal of oil from the bearing under the influence of the fan.

0 Another specific object is the provision of baffle means within the compressor crank case adjacent the fan bearing to insure the maintenance of equal pressure on the bearing and also prevent surging of oilinto the end bearing casing.

Other objects and advantages will appear from the following description of an illustrative em-. bodiment of the present invention.

In the drawings; Fig. l is a fragmentary side elevational View of a compressor embodying the teachings of the present invention and having parts broken away to more clearly disclose its structure; Fig. 2 is a vertical sectional view taken on the line 22 transversely of the compressor;

Fig. 3 is a fragmentary top plan view of the compressor with parts shown in section; Fig. 4 is a sectional View showing a. detail of the end bearing casing; and Fig. 5 is a diagrammatic showing of the path of travel of compressed air through the compressor and cooling coils. 7

The unit shown in the accompanying drawings comprises a multiple stage compressor 10 of ordinary type having low, intermediate and high pressure cylinders 11, 12, and 13 respectively. These cylinders are mounted on a crank case 14 in the usual manner and contain pistons which are actuated by connecting rods from a crank shaft 15. The crank shaft is" preferably driven from an electric motor 16 which is normally connected either directly or through suitable gearing to one end of the shaft. The other end 17 of the crank shaft 15 extends through an end bearing casing 18 and serves as adrive shaft for a fan 19 which ispreferably keyed thereto. The

fan shown is, of the suction type and-is encased in a housing 20 which is secured to arms 21 formed 5 g on the bearing casing 18. The housing 20 is provided with inlet and outlet openings 22 and 23 respectively. Obviously the outlet passage 23 may be connected by piping (notshown) to direct the air blast from thefan to any desired place 1 for discharge. v I V The compressor is mounted upon apair of leg members 24 and 25. The member 24 is formed integral with the end bearing casing 18. The leg 25 supports the motor end of the'compressor and is attached to a pair of forward lugs 26 (only one of which is shownl formedonthe-crank case 14.

A bank of coils generally indicated by the reference character 27 is composed of individual coils 28, 28?. 29 and 30. Coils 28 and 28' are connected in parallel by meansof headers 31 and 32 and serve as cooling coils for compressed airdelivered-from the low pressure cylinder 11.. This arrangement is found to be particularly desirable for the purpose of eliminating the possibilityof back pressure in the intercooler coil whena relatively large volume of air is delivered to it. The coil 29 serves as an intercooler for compressed air delivered to itfrom the cylinder 12 and the coil 30 serves as an aftercooler for air transmittedv through it from the high pressure cylin-.. der 13 to a suitable reservoir. y y

The bank of coils 2'7 is supported by brackets 33 which hang'beneath the crank case 14 and are anchored to the brackets'26 on the-crank case.

The coils 27 are housed within a. casing 34- preferably formed of sheet metaland comprising a top plate 35, secured between the lugs 26 and bracket 33, bottom and side walls 36, secured. to the plate'35, and a perforated ,end 3'7 suitably, retained in place and serving as an inlet throughwhich air may be drawn under the influence of the fan 19 to effect a cooling of the coils 27. The remaining end of the casing is provided with an opening which matches a channel 38 formed in. 1 the casing 18. This channel 38 serves to connect the coilcasing 34 with the fan housing 20.

I The compressor 10 is housed within a two part casing 39. The plate 35 serves as thebottom' of the casing 39. and a pair. of sheet metal members 0 40 form the sides thereof. Top plates 41 are secured to the side members and are adapted to abut to close the top of the casing. Latch devices 42 and 43 serve respectively as means for releasably retaining the top plates 41 in abutting relation and the sides 40 upon the base plate 35. Members 44 and 45 serve as end closures to complete the casing 39. A cut-out portion 46 in each end plate 44 abuts the crank case 14 to form a substantial seal. The members 45 abut a flange element 47 which is mounted upon the casing 18 to complete the enclosure of the compressor. The members 45 are provided with cut-out portions 48 forming an opening through which air may be drawn from the casing 39 to the fan 19. The cover plates are provided with groups of radially disposed openings 49 normally covered by rotatable discs 50. The discs 50 are provided with similarly formed openings 51 and upon manual manipulation of the discs 50 the openings 49 and 57 may be brought into registry to control the amount of air drawn into the casing 39 under the influence of the fan 19.

A horizontally disposed partition 52 serves to divide each half of the casing 39 into upper and lower compartments. The partitions are cut away to form suitable openings 53 to receive and surround the cylinders 11, 12 and 13. The upper compartment is further divided by vertically disposed partitions 54 which extend laterally across the. casing 39 to form individual chambers for the upper portions of cylinders. Apron pieces 55 which are secured to the partition 52 are provided with depending semi-circular skirts 56 adapted to lie adjacent vertically disposed fins 57 carried by the cylinders.

It will be-noted at this time that all of the cooling air drawn through the openings 49 in each chamber will pass over and around the cylinder head and through the openings 53. Thence it will be directed downwardly through the channels delineated by the fins 57 and retained in surface contact with the cylinder walls by means of the skirts 56 which surround them.'

The air will then pass over the crank case 14 and through the openings 48, into the casing 18, to the fan 19 through the opening 22 and thence be forced out through the outlet 23 formed in the fan housing 20. In this manner a regulated supply of fresh cooling air is constantly drawn through the casing 39 under the influence of the fan 19'to retain the compressor at an efficient running temperature.

A brief description of the coupling of the coils 28, 28, 29 and 30 to the cylinders 11, 12 and 13 will serve to define the path of compressed air through the cylinders and coils.- An air inlet pipe 58 is connectedto the low pressure cylinder 11 of the compressor through a suitable intake valve. Air compressed in the low pressure cylinder by the action of thepiston contained therein is directed through the usual exhaust valve to a pipe 59 which leads to a header 31 positioned in the coil casing 34. A pair of intercooling coils 28 and 28' preferably formed of brass or copper tubing are connected in parallel between the headers 31 and 32. The specific object 'of parallel connection in this coil are to afford ample volume in the coil to prevent back pressure and to expose a large surface area of tubing to permit sufficient heat convection to materially reduce the temperature of air and thus increase the efiioiency of the compressor. The compressed air is directed through a pipe-60 from the header 32 to the intake .side of the intermediate pressure cylinder 12. From this cylinder the further compressed air passes through pipe 61 to the intercooling coil 29 and from this coil through pipe 62 to the intake side of the high pressure cylinder 13. After passing through the high pressure cylinder the air is directed through the pipe 63 to an after cooling coil 30 from whence it is directed through a pipe 64 to a suitable. pressure reservoir (not shown).

It will be noted at this time that the several coils 28, 28, 29 and 30 lie adjacent one another and are supported in a suitable manner by the brackets 33 which lie wholly within the casing 34. As previously described, the casing 34 is provided with an end member 37 which is perforated throughout its entire area to insure the admission of large quantities of air. The air thus admitted passes through the casing 34 in contact with the several coils which may be provided if necessary with fins (not shown) to increase their effective areas to thus insure more rapid and complete dissipation'of heat therefrom to the cooling air. This cooling air passes from the casing 34 through the channel 38 in the casing 18 and thence to the fan 19 in a manner previously described in conjunction with the air circulation through the casing 39.

The interior of the crank case 14 is in communication with the lower compartment of the compressor casing 39 through breathers 65 which are of usual form. By reason of the fact that air in the casing 39 is under the influence of the suction fan 19, through breathers 65, the pressure in the crank case is actually below atmospheric pressure and likewise the air pressure upon cap 66 which closes the casing 18, to form a housing for an end bearing 67 of the crank shaft 15 and a fan bearing 68, is at a pressure substantially equal to the crank case pressure. This construction makes it possible to lubricate the end bearing 6'7 of the crank case in the usual manner from a force feed lubricator pump 69 through a passage 70. Oil fed to the bearing 67 is carried along the crank shaft into a cavity '71 in the casing 18. The vapor in this cavity 71 becomes oil laden to a degree which is sufiicient to insure proper lubrication for the fan bearing 68 without necessitating an independent supply of oil to this hearing. Any excess of oil which passes into the cavity 71 is directed by centrifugal force from the shaft and is deposited upon the walls of the cavity which deliver it to a passage 72 which communicates with the chamber 73 formed at the end of the crank case. The chamber 73' is enclosed by means of a housing or baflle 74 having depending end flanges 75 which terminate in openings 76 which lie below the nor-' mal oil level in the crank case.

' By reason of the above described construction it is possible to provide proper means for lubricating the end bearing of the compressor adjacent the suction fan 19 without encountering the difiiculty of having the oil so delivered sucked through the bearing under the suction of the fan;

From the foregoing specification it will readily be seen that a motor compressor unit has been provided which affords ample means for cooling the compressor and intercooling coils from a suction fan driven directly from the crank shaft of the compressor. It will also be noted that means have been provided for insuring against improper bearing lubrication due to the action of the suction fan upon the end bearing of the compressor.

While the invention has been described in considerable detail, it is understood that various changes may be made inits embodiment without departing from or sacrificing any of the advan-' tages hereinafter claimed.

Having now described my invention, what I claim as new and desire, to secure by Letters Patent, is:

l. The combination with a motor driven multiple stage compressor having intercooling coils, of means for cooling said compressor and coils, said means comprising a casing enclosing said compressor, a casing enclosing said coils, an air inlet in each of said casings, an air outlet common to both of said casings, and a fan communicating with said air outlet for inducing a flow of air through said casings to thereby extract heat from said compressor and coils.

2. In a motor driven multiple stage air compressor having intercooling coils, the combination of means for extracting heat from said com pressor and coils, said means comprising a casing enclosing said com ressor, a casing enclosing said coils, air inlets in'said casings, an air outlet common to both of said casings, baflie means in said first named casing, and means for inducing a flow of air through said casings in contact with said compressor and coils to thereby extract heat from said compressor and coils.

3. In a fluid compressor unit, the combination of cooling means for said compressor, said means comprising a casing enclosing said compressor, an air inlet in said casing, an air outlet in said casing, a suction fan communicating with. said outlet for inducing a flow of air through said casing, and means for varying the inlet opening to thereby regulate the flow of air through said casing.

4. In a motor driven multiple stage air compressor having intercooling coils, the combination of means for extracting heat from said compressor and coils, said means comprising a casing enclosing said compressor, a casing enclosing said coils, air inlets in said casings, an air outlet common to both of said casings, a suction fan communicating with said outlet opening operable to induce a flow of air through said casings in contact with said compressor and coils, and means for varying the size of said inlet openings to regulate the flow of air through said casings.

5. A cooling means for multiple stage air cornpressors having individual coils for receiving the output of each stage of compression, said means comprising a casing enclosing said compressor, a casing enclosing said coils, air inlets in. said casings, an air outlet common to both of said casings, a fan in said outlet driven by said compressor for inducing a flow of air through said casings in wiping contact with said compressor and coils to extract heat therefrom.

6. A cooling means for multiple stage air compressors having individual coils for receiving the output of each stage of compression, said means comprising a casing enclosing said compressor, a horizontally disposed partition in said casing,

bafile means carried by said partition and sur- Jrounding the compressor cylinders, a casing enclosing said coils, air inlets insaid casings, an air outlet common to both of said casings, a fan in said outlet driven by said compressor for inducing a flow of air through said casings in wip- Iing contact with said compressor and coils to extract heat therefrom.

'7. The combination with a motor driven multiple stage compressor having intercooling coils, of means for cooling said compressor and coils,

said means comprising a casing enclosing said ings to thereby extract heat from said compressor andcoils. i

8. In a motor compressor unit having cooling coils, the combination of means for extracting heat from said compressor and coils, said means comprising a suction fan driven from said compressor, a casing surrounding said coils, a casing enclosing said compressor, air inlet openings in said casings, outlet openings in said casings communicating with said fan, baiile means in said last named casing for directing the flow of air through said casings, and means for varying the size of said inlet openings to regulate the amount of air drawn through said casings by said fan.

9. In a motor compressor unit having compressor driven fan means for cooling the same, the combination of a housing forming an end plate for said compressor, an end bearing for said compressor crank shaft in said housing, a fan bearing in said housing, pressure lubricating means for said end bearing, and means for exposing both ends of said end bearing to substantially equal pressures to prevent the escape of oil from said bearing under the influence of said fan.

10. In a motor compressor unit having a suction fan driven by the compressor crank shaft, the combination of a housing forming an end plate for said compressor, an end bearing for said compressor crank shaft in said housing, and means for reducing crank case pressure to the substantial equivalent of the suction fan pressure to equalize the pressure on opposite ends of the crank shaft bearing to prevent the escape of oil due to the action of said suction fan on said bearing.

11. In a fluid compressor having cooling coils, the combination of means for extracting heat from said compressor and coils, said means comcoils, a partition in said casing dividing the same into a compressor chamber and a coil chamber, an air inlet in each of said chambers, an air outlet in each of said chambers, and means communicating with said air outlets for inducing a flow of air through said chambers tothereby extract heat from said compressor and coils.

prising a casing enclosing said compressor and 12. In a fluid compressor having cooling coils,

the combination of means for extracting heat from said compressor and coils, said means comprising a casing enclosing said compressor and 13. In a fluid compressor having cooling coils,

the combination of means for extracting heat from said compressor and coils, said means comprising a casing enclosing said compressor and coils, a partition in said casing dividing the same into a compressor chamber and a' coil chamber, means communicating with said air outlets for inducing a flow of air through said chambers, and means means surrounding each cylinder of said compressor, an air inlet in each of said chamberaan air outlet in each of said chambers, means com-v municating with said air outlets for inducinga flow of air through said chambers in wiping contact With said compressor and coils, and means operable to regulate the flow of air through said chambers.

CLYDE C. FARMER. 

